1. Field of the Invention
The present invention relates to an optical fiber and an optical device using the same.
2. Related Background Art
When light enters a highly nonlinear optical fiber, a nonlinear optical phenomena are generated in the optical fiber. Due to these nonlinear optical phenomena, light with a wavelength different from that of the incident light is newly generated in the optical fiber. Known optical devices making use of such nonlinear optical phenomena in optical fiber include, for example, light sources generating ultrabroadband (SuperContinuum) light, wavelength converters based on four-wave mixing, optical parametric amplifiers, and so on.
A dispersion-flattened optical fiber having a chromatic dispersion, whose absolute value is small and constant in a broad wavelength range, is often applied as a medium for realizing the generation of SC light, pulse compression, a switch constituted by a nonlinear optical loop mirror (NOLM), wavelength conversion, or the like. In such cases, it is often the case that better characteristics are achieved with increase of the nonlinearity of optical fiber and with expansion of the wavelength range where the chromatic dispersion is constant. However, little study from the viewpoint discussed above has been conducted heretofore.
Non-patent Document 1: J. Lee, et al., “Design and Fabrication of a Nonzero-Dispersion Fiber with a Maximally Flat Dispersion Spectrum,” IEEE Photonics Technology Letters, Vol. 13, No. 4, pp. 317-319 (2001)
Non-patent Document 2: N. Kumano, et al., “Zero Dispersion-Slope NZ-FSF with UltraWide bandwidth over 300 nm,” ECOC 2002, PD1.4
Non-patent Document 3: C. G. Joergensen, et al., “Dispersion Flattened Highly Non-Linear Fiber” ECOC-IOOC 2003, We3.7.6
Non-patent Document 4: T. Okuno, et al., “Highly nonlinear and perfectly dispersion-flattened fibres for efficient optical signal processing applications,” Electronics Letters, Vol. 39, No. 13, pp. 972-974 (2003)
Non-patent Document 5: P. S. Westbrook, et al., “Improves Supercontinuum Generation Through UV Processing of Highly Nonlinear Fibers,” Journal of Lightwave Technology, Vol. 23, No. 1, pp. 13-18 (2005)
Non-patent Document 6: F. Poletti, et al., “Ultra-flattened dispersion holey fibers: genetic algorithm design and fabrication tolerances,” CLEO/QELS 2005, CMV7